Magnetic discs with magnetizable media are used for data storage in most all computer systems. Current magnetic hard disc drives operate with the read-write heads only a few nanometers above the disc surface and at rather high speeds, typically a few meters per second. Because the read-write heads can contact the disc surface during operation, a thin layer of lubricant is coated on the disc surface to reduce wear and friction.
A conventional longitudinal recording disc medium is depicted in FIG. 1 and typically comprises a non-magnetic substrate 10 having sequentially deposited on each side thereof an underlayer 11, 11′, such as chromium (Cr) or Cr-alloy, a magnetic layer 12, 12′, typically comprising a cobalt (Co)-base alloy, and a protective overcoat 13, 13′, typically containing carbon. Conventional practices also comprise bonding a lubricant topcoat 14, 14′ to the protective overcoat. Underlayer 11, 11′, magnetic layer 12, 12′, and protective overcoat 13, 13′, are typically deposited by sputtering techniques. The Co-base alloy magnetic layer deposited by conventional techniques normally comprises polycrystallites epitaxially grown on the polycrystal Cr or Cr-alloy underlayer. A conventional perpendicular recording disc medium is similar to the longitudinal recording medium depicted in FIG. 1, but does not comprise a Cr-containing underlayer.
Generally, the lubricant is applied to the disc surface by dipping the disc in a bath containing the lubricant. The bath typically contains the lubricant and a coating solvent to improve the coating characteristics of the lubricant that is usually a viscous oil. The discs are removed from the bath, and the solvent is allowed to evaporate, leaving a thin layer of lubricant on the disc surface.